New Canaanites turning their calendars from February to March may be dreaming of many things: parking on snowless streets, walking along iceless sidewalks, cycling in slush-less bike paths. Yet the realities of March in New Canaan likely will include more snow days and Metro-North Railroad breakdowns before we see the 5,000 daffodils at Irwin Park. And before the end of the month, many of us will seek clarity on President Barack Obama’s Affordable Care Act. That’s because, as the now-stabilized healthcare.gov website reports on its homepage, open enrollment for this year ends March 31. With more than 20 years of insurance experience, town resident and New Canaan Chamber of Commerce member Brian Rogers understands the widely debated healthcare law more than most.